If so, what size resistor should I get for a 5mm LED powered by a 9V battery? Are there any other sizes you recommend?
2007-07-28 13:12:10 · 12 answers · asked by The Wise One 2 in Science & Mathematics ➔ Engineering
its multiply by 1000 difference, anyway, here' how to compute series resistance of led's:
for a 9vdc supply:
usually led's are rated 3volts to 3.4vdc and the safest range of current through them is from 20ma to 25 ma.
so:
V= IR
V=9v, I=20ma to 25 ma, voltage drop thru led= say 3volts
Vr= voltage at resistance;
Vr=V-Vled= 9-3= 6volts
R= 6/20ma= 6000/20= 300 ohms
you can select resistors from the range 230 ohms to 300 ohms, i got 230 ohms for a 25 ma current flowing to led, with a 5.8 volts drop at resistor.
2007-07-28 15:20:56 · answer #1 · answered by jesem47 3 · 2⤊ 0⤋
470 Ohm Resistor
2016-10-05 01:00:22 · answer #2 · answered by ? 4 · 0⤊ 0⤋
You have to use the 470 ohms resistor for the LED powered by a 9 volts battery. With the 470,000 ohms resistor the LED will not light.
The current in the LED will be (with the 470 ohms resistor):
I = V/R= (9-2)/470= 7/470= 15 mA ------- the 2 is the voltage drop in the led.
15 mA would be enough to light the led even when it is a bit low current, usually one uses from 20 to 25 mA to light a led.
2007-07-31 07:37:53 · answer #3 · answered by Anonymous · 0⤊ 0⤋
This Site Might Help You.
RE:
Is there a difference between 470k resistors and 470 ohm?
If so, what size resistor should I get for a 5mm LED powered by a 9V battery? Are there any other sizes you recommend?
2015-08-10 05:22:53 · answer #4 · answered by Kenda 1 · 0⤊ 0⤋
k means thousand, so there certainly is a big difference. Try the 470 ohm resistor.
2007-07-28 14:06:55 · answer #5 · answered by Renaissance Man 5 · 0⤊ 0⤋
470k means 470,000 compared to just 470ohms.
you can power the LED directly to the source without using a resistor. if you want to control the current though, better use a lower valued resistor. something in the 100 or 220 range but 470 is still ok i guess.
2007-07-28 14:42:09 · answer #6 · answered by gello15 3 · 0⤊ 0⤋
470k is 470,000 Ω. This is far too big for an LED.
I seem to recall using 330 Ω resistors when I build stuff. They were what I had laying around and worked OK.
Your 470 Ω resistor should work just fine. If you feel the LED is too dim, use a smaller resistor. If it looks too bright, increase the resistor size to something around 650 Ω.
2007-07-28 13:49:23 · answer #7 · answered by Thomas C 6 · 1⤊ 0⤋
the 470k one stands for 470,000 ohms and the other one is only 470 ohms there is quite a big difference between them, what is the LED for?
2007-07-28 13:21:04 · answer #8 · answered by Anonymous · 0⤊ 0⤋
k = 1000, thus 470k ohm = 470,000 ohm.
Required resistor size depends of the current requirement of the LED. P=IE,
2007-07-28 15:38:44 · answer #9 · answered by returnmailme 1 · 0⤊ 0⤋
470k Resistor
2016-12-17 06:38:42 · answer #10 · answered by ? 4 · 0⤊ 0⤋